Abstract
Background and aim Knee osteoarthritis (OA) is a major cause of pain, disability, and reduced quality of life, with its burden rising due to ageing, obesity, and lifestyle changes. This study analysed the trends between 1990 and 2021 in the prevalence, incidence, years lived with disability (YLDs), and disability-adjusted life years (DALYs) for knee OA across the four UK nations (England, Northern Ireland, Scotland, and Wales) using Global Burden of Disease data. Methods We extracted age-standardised and absolute estimates of prevalence, incidence, YLDs, and DALYs for knee OA in the UK and its four nations from the GBD 2021 database. Joinpoint regression analysis was applied to quantify annual percent change (APC) and average annual percent change (AAPC) in disease burden over time. Temporal patterns and inter-regional differences were assessed. Results From 1990 to 2021, the knee OA burden increased across all UK nations. England had the highest absolute prevalence, with knee OA rising from 3.02 million to 4.51 million cases (+49.2%), while Northern Ireland showed the largest relative increase (+76.4%). Women consistently had 30%-40% higher rates than men, with 2021 prevalence reaching 5,226.8 per 100,000 in England versus 3,753.2 in men. YLD rates rose by 7.16% in England and 7.94% in Scotland. DALYs increased most in Scottish men (+11.0%), and Northern Ireland recorded the fastest prevalence growth. England's burden peaked around 2015 before stabilising. Conclusion The burden of knee OA in the UK has risen markedly over the past three decades, with persistent regional disparities. These findings highlight the need for targeted prevention strategies, early diagnosis, and equitable access to joint-preserving interventions. Public health policies addressing obesity, promoting physical activity, and improving OA management could help mitigate future disease burden.